# 比較成績

grade = float(input("请输入成绩:"))
print("该学生成绩等级为：")
if (grade <= 100 and grade >= 90):
    print('A')
elif (grade < 90 and grade >= 80):
    print('B')
elif (grade < 80 and grade >= 70):
    print('C')
elif (grade < 70 and grade >= 60):
    print('D')
elif (grade >= 0 and grade < 60):
    print('E')
else:
    print("错误")
